CN217712449U - Oil casing threaded connection structure - Google Patents

Abstract

The utility model provides an oil casing threaded connection structure. Oil casing threaded connection structure includes: an externally threaded nipple; the internal thread joint is in threaded connection with the external thread joint; along the axial direction of the oil casing threaded connection structure, a first-stage threaded structure, an outer sealing structure, a second-stage threaded structure, an inner seal and a shoulder structure are sequentially formed between the outer threaded connector and the inner threaded connector from the outer side to the inner side. The technical scheme of the utility model in, this oil casing threaded connection structure can guarantee stable, reliable sealed.

Description

Oil casing threaded connection structure

Technical Field

The utility model relates to a petroleum pipe engineering technical field particularly, relates to an oil casing threaded connection structure.

Background

Along with the development environment of oil and gas fields becoming more complex, more strict requirements are put forward on the sealing performance of the threaded connection structure of the oil casing, namely the threaded connection structure can still maintain excellent sealing robustness and excellent compression performance under various complex and severe working conditions such as stretching, compression, internal pressure, external pressure, bending and the like and accidental external factors.

At present most oil casing threaded connection structure's seal structure realizes sealedly through the butt between two sealed faces, because of not setting up limit structure and removing in order to restrict sealed face for when using oil casing threaded connection structure or meeting with accidental external factor under complicated abominable operating mode, two sealed easy butt instability of face lead to sealed effect unreliable.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main aim at provides an oil casing threaded connection structure, this oil casing threaded connection structure can guarantee stable, reliable sealed.

In order to achieve the above object, the utility model provides an oil casing threaded connection structure, include: an externally threaded nipple; the internal thread joint is in threaded connection with the external thread joint; along the axial direction of the oil casing threaded connection structure, a first-stage threaded structure, an outer sealing structure, a second-stage threaded structure, an inner seal and a shoulder structure are sequentially formed between the outer threaded connector and the inner threaded connector from the outer side to the inner side.

Further, first order helicitic texture is including setting up the first order external screw thread on the outer wall face of external thread joint and the first order internal thread that sets up on the internal face of female thread joint, first order external screw thread and the cooperation of first order internal thread screw thread to make external thread joint and female thread joint threaded connection.

Further, a first-stage external thread ridge of the first-stage external thread is meshed with a first-stage internal thread ridge of the first-stage internal thread, a tooth flank clearance w is formed between the first-stage external thread ridge and the first-stage internal thread ridge, and the tooth flank clearance w satisfies the following relation: w is more than or equal to 0.02mm and less than or equal to 0.15mm.

Furthermore, the outer sealing structure comprises a first sealing part arranged on the outer threaded joint and a second sealing part arranged on the inner threaded joint, the first sealing part and the second sealing part are in interference fit, and the first sealing part and the second sealing part are both positioned between the first-stage threaded structure and the second-stage threaded structure; the first sealing portion and the second sealing portion each include at least one of a tapered surface and an arcuate surface.

Further, an included angle α 1 is formed between the first sealing portion and the axial direction of the threaded connection structure of the oil casing, and the included angle α 1 satisfies the following relationship: alpha 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; an included angle beta 1 is formed between the second sealing part and the axial direction of the threaded connection structure of the oil sleeve, and the included angle beta 1 meets the following relation: beta 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; and the included angle alpha 1 and the included angle beta 1 both satisfy the following relation: alpha 1-beta 1 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

Furthermore, the inner sealing and shoulder structure comprises a third sealing part arranged on the outer threaded joint and a fourth sealing part arranged on the inner threaded joint, the third sealing part and the fourth sealing part are in interference fit, and the third sealing part and the fourth sealing part are both positioned on one side, far away from the first-stage threaded structure, of the second-stage threaded structure; the third sealing portion and the fourth sealing portion each include at least one of a tapered surface and an arcuate surface.

Further, the nose length of the pin is L10, and the distance from the midpoint of the fourth seal portion to the first inner slope of the box is L20, where L10 and L20 satisfy the following relationship: L20/L10 is more than or equal to 0.25 and less than or equal to 0.9; and/or the length of the fourth sealing part along the axial direction of the threaded connection structure of the oil sleeve is L21, and the L21 satisfies the following relation: l21 is more than or equal to 2mm and less than or equal to 5mm.

Further, an included angle α 2 is formed between the third sealing portion and the axial direction of the threaded connection structure of the oil casing, and the included angle α 2 satisfies the following relationship: alpha 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; an included angle beta 2 is formed between the fourth sealing part and the axial direction of the threaded connection structure of the oil sleeve, and the included angle beta 2 meets the following relation: beta 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; and the included angle alpha 2 and the included angle beta 2 both satisfy the following relation: beta 2-alpha 2 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

Furthermore, the internal thread joint is also provided with a first connecting surface, one end of the first connecting surface is connected with the fourth sealing part, and the other end of the first connecting surface is connected with a first inner inclined surface of the internal thread joint; the first connection surface includes at least one of a tapered surface, a cylindrical surface, and an arc surface.

Furthermore, the inner sealing and shoulder structure further comprises a first outer inclined surface arranged on the outer threaded joint and a first inner inclined surface arranged on the inner threaded joint, and the first outer inclined surface is in interference fit with the first inner inclined surface; an included angle alpha 3 is formed between the first outer inclined plane and the vertical direction, and the included angle alpha 3 satisfies the following relation: alpha 3 is more than or equal to 0 degree and less than or equal to 15 degrees; an included angle beta 3 is formed between the first inner inclined plane and the vertical direction, and the included angle beta 3 satisfies the following relation: beta 3 is more than or equal to 0 degree and less than or equal to 15 degrees; and the included angle alpha 3 and the included angle beta 3 both satisfy the following relation: beta 3-alpha 3 is more than or equal to 0 degree and less than or equal to 1 degree.

Use the technical scheme of the utility model, oil jacket pipe threaded connection structure includes external thread joint and interior screwed joint, interior screwed joint and external thread joint threaded connection. Along the axial direction of the oil casing threaded connection structure, a first-stage threaded structure, an outer sealing structure, a second-stage threaded structure, an inner seal and a shoulder structure are sequentially formed between the outer threaded connector and the inner threaded connector from the outer side to the inner side. The external seal structure is arranged between the first-stage thread structure and the second-stage thread structure, and due to the limiting effect of the thread engagement of the inner side and the outer side of the external seal structure, the external seal structure can keep stable close contact fit in sealing contact under complex working conditions, so that the oil casing threaded connection structure has excellent external seal performance. The utility model discloses an in the embodiment, can guarantee stable, reliable sealed through oil jacket pipe threaded connection structure.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic structural view of an embodiment of a threaded connection structure for oil casings according to the present invention;

fig. 2 is a schematic view showing a male screw joint of the oil jacket pipe threaded connection structure of fig. 1;

fig. 3 is a schematic view showing a female screw joint of the oil jacket pipe threaded connection structure of fig. 1;

fig. 4 shows a partially enlarged view of a first-stage thread structure a of the oil jacket threaded connection structure of fig. 1;

FIG. 5 shows an enlarged view of the pin joint of FIG. 2 at b 1;

fig. 6 shows an enlarged view of the female joint of fig. 3 at b 2;

FIG. 7 shows a partially enlarged view of a second-step thread structure c of the oil jacket threaded connection of FIG. 1;

FIG. 8 is a partial enlarged view of an inner seal and shoulder structure d of the oil jacket threaded connection of FIG. 1;

FIG. 9 shows an enlarged view of the pin joint of FIG. 2 at d 1;

fig. 10 shows an enlarged view of the female coupling of fig. 3 at d 2;

fig. 11 is a graph showing the relationship between the sealing contact pressure and the sealing contact length of the external sealing structure under the working condition of stretching and external pressure according to the conventional technology of the threaded connection structure of the oil casing and the external sealing at the pipe end of the present invention; and

fig. 12 shows a quantitative index of sealing performance based on finite element analysis of the threaded connection structure of oil casing according to the present invention and a L20/L10 relationship diagram.

Wherein the figures include the following reference numerals:

1. an externally threaded nipple; 2. an internal thread joint; 10. a first-stage external thread; 11. a first seal portion; 12. a second-stage external thread; 13. a third seal portion; 14. a first outer bevel; 15. an inclined surface; 20. a first-stage internal thread; 21. a second seal portion; 22. a second-stage internal thread; 23. a fourth seal portion; 24. a first connection face; 25. a first inner inclined surface.

Detailed Description

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present application, where the contrary is not intended, the use of directional words such as "upper, lower, top and bottom" is generally with respect to the orientation shown in the drawings, or with respect to the component itself in the vertical, perpendicular or gravitational direction; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

Along with the development environment of oil and gas fields becoming more complex, stricter requirements are put forward on the sealing performance of the threaded connection structure of the oil sleeve, namely, the threaded connection structure can still maintain excellent sealing robustness and excellent compression performance under various complex and severe working conditions such as stretching, compression, internal pressure, external pressure, bending and the like and accidental external factors.

The standard API (American Petroleum Institute) threaded oil casing has the problems of low connection strength of a threaded joint, poor composite load resistance, no air tightness and the like due to the design defects of the casing, and cannot be qualified in harsh well conditions, and is mainly used for well conditions with low requirements on working conditions such as shallow wells, low-pressure wells and the like.

Chinese patent (publication No. CN 203925329U) discloses a utility model patent entitled "a hermetic sealing oil casing joint", the technical thread of this patent is a buttress structure, parallel thread bus at the bottom of the tooth top, the design of external thread joint end has first location circular bead and first sealed face, female thread joint design has corresponding second location circular bead and second sealed face, first sealed face and second sealed face are the conical surface that the angle of inclination is beta, wherein 0.1 is more than or equal to tan beta and is less than or equal to 1.8, the seal structure of this kind of comparatively traditional structure is close to the circular bead, its sealing performance seriously receives the stress condition influence of location circular bead, sealing performance's stability is not high.

Chinese patent (publication No. CN 2575286Y) discloses a utility model patent named "oil, sleeve threaded joint", this patent technology screw thread is the partial trapezoidal structure of modified, and seal structure has adopted outer seal face to be the cylinder, and interior seal face is the structure of sphere, and this seal structure's production and processing and detection difficulty, the easy unexpected damage of seal structure moreover.

Chinese patent (publication No. CN 100390454C) discloses an invention patent entitled "improved threaded pipe connection comprising at least one threaded element with an end lip", which is designed with an "attachment" between the sealing surface and the shoulder, which is not on the same circumferential surface as the sealing surface. The sealing structure is complex to process, an additional accessory structure needs to be processed, the angle of a sealing surface of the sealing structure is at least 10 degrees, the thickness of the shoulder is thinner due to the fact that the angle of the sealing surface is too large, and the compression performance is influenced to a certain extent.

Chinese patent (publication No. CN 102313085A) discloses an invention patent named as a threaded connector for a pipe, the technology of the invention adopts a sealing structure with three sections of cambered surfaces connected, the production, the processing and the detection of the sealing structure are difficult, and the sealing structure is easy to damage a thread gluing.

At present most oil casing threaded connection structure exists when using oil casing threaded connection structure or meeting with accidental external factor under complicated abominable operating mode, and two sealed faces butt unstability easily leads to the unreliable problem of sealed effect.

Moreover, the sealing contact length is too long, which causes the sealing contact pressure to be reduced, thereby affecting the sealing performance; too short sealing contact length can cause too high sealing contact pressure and possibly cause the sealing surface to be sticky; the distance between the seal contact portion and the pipe end affects the seal contact state and the compression performance of the oil casing threaded connection structure.

In order to solve the problem, the utility model discloses an embodiment provides an oil casing threaded connection structure.

As shown in fig. 1 to 10, in the embodiment of the present invention, the oil casing threaded connection structure includes a male adapter 1 and a female adapter 2, and the male adapter 1 and the female adapter 2 are screwed together. The external thread joint 1 is processed on the outer surface of a pipe end, and comprises a first-stage external thread 10, a first sealing part 11, a second-stage external thread 12, a third sealing part 13, a first external inclined surface 14 and an inclined surface 15 from a steel pipe body to the main structure of the pipe end in sequence. The female adapter 2 is processed on the inner surface of the pipe end, and the main structures from the pipe end to the steel pipe body are a first-stage female thread 20, a second sealing part 21, a second-stage female thread 22, a fourth sealing part 23, a first connecting surface 24 and a first inner inclined surface 25 in sequence.

As shown in fig. 1 to 3, in the embodiment of the present invention, the oil casing threaded connection structure includes an external thread joint 1 and an internal thread joint 2, and the internal thread joint 2 is in threaded connection with the external thread joint 1; along the axial direction of the oil casing threaded connection structure, a first-stage threaded structure a, an outer sealing structure b, a second-stage threaded structure c and an inner sealing and shoulder structure d are sequentially formed between the external thread joint 1 and the internal thread joint 2 from the outer side to the inner side.

In the above-mentioned setting, oil jacket pipe threaded connection structure includes external thread joint 1 and internal thread joint 2, internal thread joint 2 and external thread joint 1 threaded connection. Along the axial direction of the oil casing threaded connection structure, a first-stage thread structure a, an outer sealing structure b, a second-stage thread structure c and an inner sealing and shoulder structure d are sequentially formed between the external thread connector 1 and the internal thread connector 2 from the outer side to the inner side. The external sealing structure b is arranged between the first-stage thread structure a and the second-stage thread structure c, and due to the limiting effect of the thread meshing of the inner side and the outer side of the external sealing structure b, the external sealing structure b can be in stable close contact fit in sealing contact under complex working conditions, so that the oil casing threaded connection structure has excellent external sealing performance. The utility model discloses an in the embodiment, can guarantee stable, reliable sealed through oil jacket pipe threaded connection structure.

The embodiment of the utility model provides an in, oil jacket pipe threaded connection structure is an oil jacket pipe screwed joint who has excellent external pressure sealing performance, interior pressure sealing performance and compressibility, and this screwed joint still has good structural integrity and sealed integrality under the abominable load operating mode of various complicacies, has excellent sealed robustness simultaneously, applicable in the oil gas well that geological conditions such as high temperature, high pressure, extra-deep are complicated.

As shown in fig. 2 to 4, in the embodiment of the present invention, the first-stage thread structure a includes a first-stage male thread 10 (shown as a1 in fig. 2) provided on the outer wall surface of the male connection end 1 and a first-stage female thread 20 (shown as a2 in fig. 3) provided on the inner wall surface of the female connection end 2, and the first-stage male thread 10 and the first-stage female thread 20 are in thread fit with each other, so that the male connection end 1 is in thread connection with the female connection end 2.

Among the above-mentioned setting, threaded connection mode simple structure, firm in connection is convenient for assemble and dismantlement.

As shown in fig. 1 and 4, in the embodiment of the present invention, the first-stage male thread ridge of the first-stage male thread 10 and the first-stage female thread ridge of the first-stage female thread 20 are engaged with each other, and a flank clearance w is provided between the first-stage male thread ridge and the first-stage female thread ridge, and the flank clearance w satisfies the following relationship: w is more than or equal to 0.02mm and less than or equal to 0.15mm.

First order external screw thread 10 sets up on external thread joint 1, and first order internal thread 20 sets up on internal thread joint 2, and the threaded connection between first order external screw thread 10 and the first order internal thread 20 is realized to the meshing of the first order external screw thread of first order external screw thread 10 and the first order internal thread of first order internal thread 20. When the first-stage external thread ridge and the first-stage internal thread ridge are engaged, a tooth flank clearance w is formed between the first-stage external thread ridge and the first-stage internal thread ridge, and the tooth flank clearance w satisfies a given range: if w is too small, thread teeth are easy to damage and thread gluing in the operation process; if w is too large, the compression performance of the threaded connection structure of the oil sleeve is affected; the reasonable range of the tooth flank clearance w is more than or equal to 0.02mm and less than or equal to 0.15mm, and the oil sleeve threaded connection structure can have good screwing operation performance and compression performance at the same time through the arrangement.

As shown in fig. 1 to 3, 5 and 6, in an embodiment of the present invention, the outer seal structure b (shown as b in fig. 1) includes a first seal portion 11 (shown as b1 in fig. 2 and 5) disposed on the outer threaded joint 1 and a second seal portion 21 (shown as b2 in fig. 3 and 6) disposed on the inner threaded joint 2, the first seal portion 11 and the second seal portion 21 are in interference fit, and the first seal portion 11 and the second seal portion 21 are both located between the first-stage threaded structure a and the second-stage threaded structure c; the first seal portion 11 and the second seal portion 21 are tapered surfaces.

In the above arrangement, the first seal portion 11 of the male joint 1 and the second seal portion 21 of the female joint 2 are interference-fitted in the radial direction, so that a sealing effect is produced and external sealing is achieved.

The first sealing part 11 of the external thread joint 1 is arranged between the first-stage external thread 10 and the second-stage external thread 12, the second sealing part 21 of the internal thread joint 2 is arranged between the first-stage internal thread 20 and the second-stage internal thread 22, and due to the limiting effect of the thread engagement of the inner side and the outer side, the sealing contact of the first sealing part 11 and the second sealing part 21 under the complex working condition can keep stable close contact fit, so that the oil casing thread connecting structure has excellent external sealing performance.

The embodiment of the utility model provides an in, first sealing 11 of external thread joint 1 and second sealing 21 of female thread joint 2 can be conical surface or cambered surface or by the compound face that the conical surface makes up with the cambered surface, utilizes finite element analysis all can realize better sealing contact pressure and sealing contact length.

Through finite element analysis, the correlation between the sealing contact pressure and the sealing contact length of the external sealing structure under the working condition of stretching and combining external pressure (the working condition is the most harsh working condition of external pressure) is contrastively analyzed with the traditional technology that the external sealing is positioned at the pipe end, as shown in fig. 11, as the sealing performance is the comprehensive determination of the sealing contact pressure and the sealing contact length, the quantitative index of the sealing performance can be represented by integrating the sealing contact pressure on the sealing contact length (namely the area enclosed by a curve), and it can be seen that the integral area of the technology is far larger than that of the traditional technology that the external sealing is positioned at the pipe end, and the technology has better sealing quantitative index.

This is because the oil casing threaded joint of the conventional art in which the external seal is located at the pipe end causes a certain expansion of the pipe end of the female threaded joint 2 due to the pipe end effect, and at the same time, the male threaded joint 1 causes a certain reduction of the diameter under the external pressure, so that the closer the seal surface is to the pipe end, the more the separation tends to be, and the worse the seal contact state is. In the technical scheme of the application, due to the limiting effect of the thread engagement of the inner side and the outer side, the first sealing part 11 and the second sealing part 21 can be kept in stable close contact fit under complex working conditions, and therefore the oil sleeve threaded connection structure has excellent external sealing performance.

Of course, in alternative embodiments of the present application, the first sealing portion 11 may also be made to be an arc surface, or the first sealing portion 11 includes a conical surface and an arc surface connected to each other, or the second sealing portion 21 is made to be an arc surface, or the second sealing portion 21 includes a conical surface and an arc surface connected to each other.

As shown in fig. 5 and fig. 6, in the embodiment of the present invention, an included angle α 1 is formed between the first sealing portion 11 and the axial direction of the threaded connection structure of the oil casing, and the included angle α 1 satisfies the following relationship: alpha 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; an included angle beta 1 is formed between the second sealing part 21 and the axial direction of the threaded connection structure of the oil sleeve, and the included angle beta 1 satisfies the following relation: beta 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; and the included angle alpha 1 and the included angle beta 1 both satisfy the following relation: alpha 1-beta 1 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

The embodiment of the utility model provides an in, contained angle alpha 1 that first sealing 11 of external thread joint 1 corresponds satisfies the angle scope and does: alpha 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees, and the included angle beta 1 corresponding to the second sealing part 21 of the female adapter 2 satisfies the following angle ranges: beta 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees, and the included angle alpha 1 and the included angle beta 1 both satisfy the following relations: alpha 1-beta 1 is more than or equal to 0 degree and less than or equal to 1.5 degrees, and the arrangement can compensate the reduction of the sealing contact pressure at one side close to the pipe end caused by the neck expansion of the pipe end of the female adapter 2 and the external pressure action, thereby achieving the uniform distribution of the sealing contact pressure and realizing the steady sealing effect. Through the arrangement, the oil sleeve threaded connection structure has an excellent sealing distribution state and good sealing surface anti-sticking performance.

Preferably, the included angle α 1 and the included angle β 1 both satisfy the following relationship: alpha 1-beta 1 is more than or equal to 0.2 degrees and less than or equal to 0.5 degrees.

As shown in fig. 7, in the embodiment of the present invention, the second-stage thread structure c includes a second-stage male thread 12 (shown as c1 in fig. 2) provided on the outer wall surface of the male connection end 1 and a second-stage female thread 22 (shown as c2 in fig. 3) provided on the inner wall surface of the female connection end 2, and the second-stage male thread 12 is in threaded engagement with the second-stage female thread 22, so that the male connection end 1 is in threaded connection with the female connection end 2.

As shown in fig. 7, in the embodiment of the present invention, the second-stage male thread ridge of the second-stage male thread 12 and the second-stage female thread ridge of the second-stage female thread 22 are engaged with each other, and the flank clearance w is provided between the second-stage male thread ridge and the second-stage female thread ridge, and satisfies the following relationship: w is more than or equal to 0.02mm and less than or equal to 0.15mm.

The second-stage male thread ridges of the second-stage male threads 12 are engaged with the second-stage female thread ridges of the second-stage female threads 22 to realize the threaded connection between the first-stage male threads 10 and the first-stage female threads 20. The flank clearance w between the second-step male thread ridge and the second-step female thread ridge satisfies the following relationship: w is more than or equal to 0.02mm and less than or equal to 0.15mm. Through the arrangement, the oil casing threaded connection structure can have good screwing operation performance and compression performance at the same time.

As shown in fig. 1 to 3, 9 and 10, in an embodiment of the present invention, the inner seal and shoulder structure d (shown as d in fig. 1) includes a third seal portion 13 (shown as d1 in fig. 2) disposed on the external thread joint 1 and a fourth seal portion 23 (shown as d2 in fig. 3) disposed on the internal thread joint 2, the third seal portion 13 and the fourth seal portion 23 are in interference fit, and the third seal portion 13 and the fourth seal portion 23 are both located on one side of the second-stage thread structure c away from the first-stage thread structure a; the third seal portion 13 and the fourth seal portion 23 are both tapered surfaces.

In the above arrangement, the third seal portion 13 of the male joint 1 and the fourth seal portion 23 of the female joint 2 are interference-fitted in the radial direction, thereby producing a sealing effect.

The third sealing portion 13 provided on the male connection end 1 and the fourth sealing portion 23 provided on the female connection end 2 may be tapered surfaces or cambered surfaces or composite surfaces formed by combining tapered surfaces and cambered surfaces, and superior sealing contact pressure and sealing contact length can be achieved by using a finite element analysis method.

Of course, in the alternative embodiment of the present application, the third sealing portion 13 may also be an arc surface according to actual needs; or, the third sealing part 13 comprises a conical surface and an arc surface which are connected; alternatively, the fourth seal portion 23 is formed as a curved surface; alternatively, the fourth seal portion 23 may include a tapered surface and a curved surface that are connected.

As shown in fig. 9 and 10, in the embodiment of the present invention, the nose length of the male screw joint 1 is L10, and the distance from the midpoint of the fourth sealing portion 23 to the first inner inclined surface 25 of the female screw joint 2 is L20, where L10 and L20 satisfy the following relationship: L20/L10 is more than or equal to 0.25 and less than or equal to 0.9.

In the embodiment of the present invention, the distance L20 from the midpoint of the fourth sealing portion 23 of the female screw joint 2 to the first inner inclined surface 25 and the nose length L10 of the male screw joint 1 satisfy the predetermined relationship. The smaller the value of L20/L10, the closer the inner seal contact area is to the shoulder, which results in the inner seal contact state being susceptible to the influence of the adjacent stressed shoulder (interference fit of the first outer inclined surface 14 and the first inner inclined surface 25), thereby affecting the sealing performance; meanwhile, the smaller the L20/L10 value is, the closer the inner seal contact area is to the shoulder contact part, and when the oil sleeve threaded connection is compressed, the shorter the compression deformation energy storage length from the inner seal contact area to the shoulder contact part is, so that the compression performance is influenced. Meanwhile, the smaller the value of L20/L10, the closer the inner seal contact area is to the pipe end, and the more the third seal portion 13 of the external pressure-to-external threaded joint 1 tends to be reduced in diameter, resulting in the more the contact state between the third seal portion 13 of the external threaded joint 1 and the fourth seal portion 23 of the internal threaded joint 2 tends to be separated, thereby affecting the sealing performance. As the value L20/L10 increases, the inner seal surface of the female screw joint 2 tends to expand in diameter under the internal pressure, and the contact state between the third seal portion 13 of the male screw joint 1 and the fourth seal portion 23 of the female screw joint 2 tends to separate, thereby affecting the sealing performance. After finite element analysis, as shown in fig. 12, P represents the seal contact pressure and x represents the seal contact length, since the sealing performance is a comprehensive determination of the seal contact pressure and the seal contact length, therefore, the quantitative index ^ xPdx of the sealing performance is represented by integrating the sealing contact pressure P with the sealing contact length x, and the better quantitative index of the sealing performance is shown when the sealing contact pressure P is more than or equal to 0.25 and less than or equal to L20/L10 and less than or equal to 0.9. Therefore, a reasonable range of L20/L10 values is 0.25 ≦ L20/L10 ≦ 0.9. The arrangement is such that the oil casing threaded connection structure has good sealing performance and compression performance at the same time.

Preferably, 0.65. Ltoreq. L20/L10. Ltoreq.0.85.

As shown in fig. 10, in the embodiment of the present invention, along the axial direction of the oil casing threaded connection structure, the length of the fourth sealing portion 23 is L21, and L21 satisfies the following relationship: l21 is more than or equal to 2mm and less than or equal to 5mm.

The embodiment of the utility model provides an in, the length range of the length L21 of the fourth sealing of female adapter 2 is: l21 is more than or equal to 2mm and less than or equal to 5mm. By the arrangement, comprehensive and excellent sealing contact pressure and sealing contact length can be realized.

Preferably, 2.2mm L21 is less than or equal to 3.5mm.

As shown in fig. 9 and 10, in the embodiment of the present invention, an included angle α 2 is formed between the third sealing portion 13 and the axial direction of the threaded connection structure of the oil casing, and the included angle α 2 satisfies the following relationship: alpha 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; an included angle beta 2 is formed between the fourth sealing portion 23 and the axial direction of the threaded connection structure of the oil casing, and the included angle beta 2 satisfies the following relation: beta 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees; and the included angle alpha 2 and the included angle beta 2 both satisfy the following relation: beta 2-alpha 2 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

The included angle alpha 2 corresponding to the third sealing part 13 of the male thread joint 1 meets the following angle range: alpha 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees, and the included angle beta 2 corresponding to the fourth sealing part 23 of the female adapter 2 meets the following angle range: beta 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees, and the included angle alpha 2 and the included angle beta 2 both satisfy the following relations: beta 2-alpha 2 is more than or equal to 0 degree and less than or equal to 1.5 degrees. By the arrangement, the reduction of the sealing contact pressure close to one side of the pipe end due to the necking of the pipe end and the internal pressure effect can be compensated, so that the uniform distribution of the sealing contact pressure is achieved, and the stable sealing effect is realized. Through the arrangement, the oil sleeve threaded connection structure has an excellent sealing distribution state and good sealing surface anti-sticking performance.

Preferably, 0.2 DEG-beta 2-alpha 2 DEG-0.5 deg.

As shown in fig. 8 and 10, in the embodiment of the present invention, the female connector 2 is further provided with a first connection surface 24, one end of the first connection surface 24 is connected to the fourth sealing portion 23, and the other end of the first connection surface 24 is connected to the first inner inclined surface 25 of the female connector 2; the first connection surface 24 includes at least one of a conical surface, a cylindrical surface, and an arc surface.

In the embodiment of the present invention, the first connection surface 24 and the fourth sealing portion 23 of the female adapter 2 are not on the same circumferential surface, and the first connection surface 24 may be formed by combining various line segments and/or arc surfaces.

The distance L20 from the midpoint of the fourth sealing portion 23 of the female adapter 2 to the first inner inclined surface 25 and the nose length L10 of the male adapter 1 satisfy a set relationship, and the circumferential surface (i.e., the first connecting surface 24) from the fourth sealing portion 23 to the first inner inclined surface 25 and the fourth sealing portion 23 are not on the same circumferential surface, and the first connecting surface 24 may be formed by combining a plurality of line segments and/or arc surfaces, so that the rigidity of the inner sealing portion (i.e., the third sealing portion 13 and the fourth sealing portion 23 are in interference fit in the radial direction) is improved, which is beneficial to improving the sealing performance of the oil casing threaded connection structure under internal pressure, and the inner sealing contact pair can maintain stable close contact fit, so that the oil casing threaded connection structure has excellent inner sealing performance.

As shown in fig. 8, in an embodiment of the present invention, the first connection surface 24 of the female connector 2 and the third sealing portion 13 of the male connector 1 may be in non-contact or partial contact (as shown by the dotted lines in fig. 8 and 10).

As shown in fig. 9 and 10, in the embodiment of the present invention, the inner seal and shoulder structure d further includes a first outer inclined surface 14 disposed on the outer threaded joint 1 and a first inner inclined surface 25 disposed on the inner threaded joint 2, and the first outer inclined surface 14 is in interference fit with the first inner inclined surface 25; wherein, the first outer inclined surface 14 has an included angle α 3 with the vertical direction, and the included angle α 3 satisfies the following relationship: alpha 3 is more than or equal to 0 degree and less than or equal to 15 degrees; the first inner inclined surface 25 has an included angle β 3 with the vertical direction, and the included angle β 3 satisfies the following relationship: beta 3 is more than or equal to 0 degree and less than or equal to 15 degrees; and the included angle alpha 3 and the included angle beta 3 both satisfy the following relation: beta 3-alpha 3 is more than or equal to 0 degree and less than or equal to 1 degree.

In the embodiment of the present invention, the first outer inclined surface 14 and the first inner inclined surface 25 are in interference contact with each other, so as to achieve the functions of screwing, positioning and compression resistance.

The embodiment of the utility model provides an in, contained angle alpha 3 that first outer inclined plane 14 of external thread joint 1 corresponds satisfies the angle scope and does: alpha 3 is more than or equal to 0 degree and less than or equal to 15 degrees, and the included angle beta 3 corresponding to the first inner inclined surface 25 of the female adapter 2 satisfies the following angle ranges: beta 3 is more than or equal to 0 degree and less than or equal to 15 degrees, and the included angle alpha 3 and the included angle beta 3 both satisfy the following relations: beta 3-alpha 3 is more than or equal to 0 degree and less than or equal to 1 degree. Set up like this, compensated because the influence of external thread joint body pipe end necking down causes being close to the reduction of intraductal side shoulder magnitude of interference for the shoulder surface atress is comparatively even after the interference contact between the shoulder, thereby makes oil casing threaded connection structure have good compression performance, is of value to good contact between third sealing 13 and the fourth sealing 23 simultaneously.

Preferably, 0.2 DEG-beta 3-alpha 3 DEG-0.8 deg.

As shown in fig. 9, in the embodiment of the present invention, the male connector 1 has the inclined surface 15, the inclined surface 15 is provided on a part of the inner wall surface of the male connector 1, and the inclined surface 15 is gradually away from the axis of the oil casing threaded connection structure and connected to the first outer inclined surface 14 along the axial direction of the oil casing threaded connection structure.

The embodiment of the utility model provides an in, inclined plane 15 can be single conical surface, also can be the compound face of making up by cylinder and conical surface, through design processing inclined plane 15, can prevent that rolling state steel pipe circumference wall thickness inequality from leading to the fact inhomogeneous unstable contact state to the internal seal contact pair (third sealing 13 and fourth sealing 23), makes simultaneously screwed joint 1 and female adapter 2 keep interior the flushing in the hole department of first outer inclined plane 14 and the contact of first inner inclined plane 25, prevents to produce the turbulent flow.

As shown in fig. 9, in the embodiment of the present invention, an included angle α 4 is formed between the inclined surface 15 of the male adapter 1 and the axial direction of the oil casing threaded connection structure, and the included angle α 4 satisfies the following relationship: alpha 4 is more than or equal to 6 degrees and less than or equal to 20 degrees.

The embodiment of the utility model provides an in, oil jacket pipe threaded connection structure has following advantage:

1. the first sealing part 11 of the male adapter 1 and the second sealing part 21 of the female adapter 2 are in interference fit in the radial direction, so that a sealing effect is generated, and external sealing is realized; the third seal portion 13 of the male joint 1 and the fourth seal portion 23 of the female joint 2 are interference-fitted in the radial direction, thereby producing a sealing effect, achieving internal sealing. The inner sealing structure and the outer sealing structure are adopted to realize independent inner and outer double sealing, and the sealing is more reliable;

2. based on finite element analysis, optimized sealing surface structure parameters are adopted, and the sealing integrity and the sealing robustness of the threaded joint are greatly improved;

3. the setting of the angle relation of the outer sealing surface, the angle relation of the inner sealing surface and the angle relation of the shoulder surface compensates the influence caused by uneven pressure of the contact part, realizes a stable sealing effect and realizes good compression performance.

The embodiment of the utility model provides an in, oil casing threaded connection structure is a high performance oil casing screwed joint, and mainly used is to the harsh well condition of external compressed air sealing performance, interior compressed air sealing performance and compression performance requirement. The threaded connection structure of oil casing is a threaded joint mainly used for oil casings in the petroleum industry, and is a tubular connection element in the technical field of petroleum pipes.

The technical scheme of the application is applied as follows:

example one

The utility model discloses an in the embodiment one, the body adopts 273.05 x 13.84mm specification sleeve pipe, and the steel grade is P110, adopts API standard to prescribe the coupling external diameter, and the material property satisfies API standard requirement.

The geometrical parameters of the threaded connection are as follows: thread taper 1, thread pitch 5 threads/inch, outer seal structure disposed between the first and second thread structures, α 1=7.1 °, β 1=6.7 °, w =0.4mm, L20/L10=0.75, L21=3.5mm, α 3=8 °, β 3=8.5 °, α 4=10 °.

The connection strength of the threaded connection structure of the casing pipe reaches 8550kN, the compression strength reaches 8550kN, the internal pressure sealing performance reaches more than 68MPa, the external pressure performance reaches more than 41MPa, the bending resistance reaches more than 20 degrees/30 meters, and the requirement of no thread gluing during the process of 3 times of shackle removal is met. The threaded connection structure of the sleeve has excellent internal pressure sealing performance, external pressure sealing performance and compression performance.

Example two

The utility model discloses an in the second embodiment, 88.9X 9.52mm specification oil pipe is adopted to the body, and the steel grade is P110, adopts API standard regulation coupling external diameter, and the material property satisfies API standard requirement.

The geometrical parameters of the threaded connection are as follows: thread taper 1, thread pitch 5 threads/inch, outer seal structure disposed between the first and second thread structures, α 1=7.1 °, β 1=6.7 °, w =0.3mm, L20/L10=0.80, L24=3.5mm, α 3=8 °, β 3=8.5 °, α 4=10 °.

The connection strength of the threaded connection structure of the casing pipe reaches 1800kN, the compression strength reaches 1800kN, the internal pressure sealing performance reaches more than 142Mpa, the external pressure sealing performance reaches more than 145Mpa, the bending resistance reaches more than 45 degrees/30 meters, and the threaded connection structure of the casing pipe meets the requirement that the casing pipe is broken out and does not thread gluing for 10 times. The oil casing threaded connection structure has excellent internal pressure sealing performance, external pressure sealing performance and compression performance.

From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the oil casing threaded connection structure comprises an external thread joint and an internal thread joint, and the internal thread joint is in threaded connection with the external thread joint. Along the axial direction of the oil casing threaded connection structure, a first-stage threaded structure, an outer sealing structure, a second-stage threaded structure, an inner seal and a shoulder structure are sequentially formed between the outer threaded connector and the inner threaded connector from the outer side to the inner side. The external seal structure is arranged between the first-stage thread structure and the second-stage thread structure, and due to the limiting effect of the thread engagement of the inner side and the outer side of the external seal structure, the external seal structure can keep stable close contact fit in sealing contact under complex working conditions, so that the oil casing threaded connection structure has excellent external seal performance. The utility model discloses an in the embodiment, can guarantee stable, reliable sealed through oil jacket pipe threaded connection structure.

It is obvious that the above described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The utility model provides an oil casing threaded connection structure which characterized in that includes:

a male coupling (1);

the internal thread joint (2) is in threaded connection with the external thread joint (1);

along the axial of oil casing threaded connection structure, screwed joint (1) with be formed with first order helicitic texture (a), external seal structure (b), second level helicitic texture (c) and interior seal and circular bead structure (d) to the inboard by the outside in proper order between screwed joint (2).

2. The threaded connection structure for oil casings according to claim 1, characterized in that the first-stage threaded structure (a) includes a first-stage male thread (10) provided on the outer wall surface of the male connector (1) and a first-stage female thread (20) provided on the inner wall surface of the female connector (2), the first-stage male thread (10) and the first-stage female thread (20) being threadedly engaged to threadedly connect the male connector (1) with the female connector (2).

3. The threaded oil casing connection according to claim 2, characterized in that a first step male thread ridge of the first step male thread (10) and a first step female thread ridge of the first step female thread (20) are engaged, and a flank clearance w is provided therebetween, the flank clearance w satisfying the following relationship: w is more than or equal to 0.02mm and less than or equal to 0.15mm.

4. The oil casing threaded connection according to any one of claims 1 to 3, characterized in that the outer seal structure (b) includes a first seal portion (11) provided on the pin (1) and a second seal portion (21) provided on the box (2), the first seal portion (11) and the second seal portion (21) are in interference fit, and the first seal portion (11) and the second seal portion (21) are both located between the first-stage thread structure (a) and the second-stage thread structure (c);

the first seal portion (11) and the second seal portion (21) each include at least one of a tapered surface and an arc surface.

5. The oil casing threaded connection structure according to claim 4,

an included angle alpha 1 is formed between the first sealing portion (11) and the axial direction of the oil sleeve threaded connection structure, and the included angle alpha 1 meets the following relation: alpha 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees;

the second sealing part (21) and the axial direction of the oil sleeve threaded connection structure form an included angle beta 1, and the included angle beta 1 meets the following relation: beta 1 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees;

and the included angle alpha 1 and the included angle beta 1 both satisfy the following relation: alpha 1-beta 1 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

6. A threaded connection according to any one of claims 1 to 3, characterized in that the internal seal and shoulder structure (d) comprises a third seal portion (13) provided on the male connection (1) and a fourth seal portion (23) provided on the female connection (2), the third seal portion (13) and the fourth seal portion (23) being in interference fit, the third seal portion (13) and the fourth seal portion (23) both being located on the side of the second-stage thread structure (c) remote from the first-stage thread structure (a);

the third seal portion (13) and the fourth seal portion (23) each include at least one of a tapered surface and an arc surface.

7. The oil casing threaded connection structure according to claim 6,

the nose length of the male adapter (1) is L10, the distance from the midpoint of the fourth sealing portion (23) to the first inner inclined surface (25) of the female adapter (2) is L20, wherein L10 and L20 satisfy the following relationship: L20/L10 is more than or equal to 0.25 and less than or equal to 0.9; and/or the presence of a gas in the gas,

the length of the fourth sealing part (23) along the axial direction of the oil casing threaded connection structure is L21, and L21 satisfies the following relation: l21 is more than or equal to 2mm and less than or equal to 5mm.

8. The oil casing threaded connection structure according to claim 6,

an included angle alpha 2 is formed between the third sealing part (13) and the axial direction of the oil sleeve threaded connection structure, and the included angle alpha 2 meets the following relation: alpha 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees;

an included angle beta 2 is formed between the fourth sealing portion (23) and the axial direction of the oil sleeve threaded connection structure, and the included angle beta 2 meets the following relation: beta 2 is more than or equal to 3.50 degrees and less than or equal to 9.90 degrees;

and the included angle alpha 2 and the included angle beta 2 both satisfy the following relation: beta 2-alpha 2 is more than or equal to 0 degree and less than or equal to 1.5 degrees.

9. The threaded connection structure for oil casings according to claim 6, characterized in that a first connection surface (24) is further provided on the female adapter (2), one end of the first connection surface (24) is connected with the fourth sealing portion (23), and the other end of the first connection surface (24) is connected with a first inner inclined surface (25) of the female adapter (2); the first connection surface (24) includes at least one of a conical surface, a cylindrical surface, and an arcuate surface.

10. The oil casing threaded connection according to any one of claims 1 to 3, characterized in that the internal seal and shoulder structure (d) further comprises a first external chamfer (14) provided on the pin (1) and a first internal chamfer (25) provided on the box (2), the first external chamfer (14) being an interference fit with the first internal chamfer (25); wherein,

the first outer inclined surface (14) and the vertical direction form an included angle alpha 3, and the included angle alpha 3 satisfies the following relation: alpha 3 is more than or equal to 0 degree and less than or equal to 15 degrees;

an included angle beta 3 is formed between the first inner inclined plane (25) and the vertical direction, and the included angle beta 3 satisfies the following relation: beta 3 is more than or equal to 0 degree and less than or equal to 15 degrees;

and the included angle alpha 3 and the included angle beta 3 both satisfy the following relation: beta 3-alpha 3 is more than or equal to 0 degree and less than or equal to 1 degree.

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